Metal wall material and wall construction method using same

ABSTRACT

A metal wall material  1  according to the present invention comprises: a front substrate  10  made of a metal sheet, the front substrate  10  comprising a body portion  100  formed into a box shape; a back substrate  11  arranged on a back side of the front substrate  10  so as to cover an opening of the body portion  100 ; and a core material  12  filled between the body portion  100  and the back substrate  11 , the metal wall material  1  being tightened to a wall base by driving at least one tightening member into the body portion  100 , wherein a top plate portion  101  of the body portion  100  comprises at least one protruding rib  3  comprised of at least one protrusion  30  disposed along a side of a polygon or along a circle, and wherein the metal wall material  1  is configured such that the tightening member is driven into an inner region  3 a of the protruding rib  3.

TECHNICAL FIELD

The present invention relates to a metal wall material that is tightenedon a wall base by driving a tightening member, and a wall constructionmethod using the same.

BACKGROUND ART

The present inventors have attempted implementation of a surface memberfor overlap roofing as disclosed in the following Patent Document 1,i.e., a metal wall material including a metal front substrate; a backsubstrate disposed on a back side of the front substrate; and a corematerial made of a foamed resin filled between the front substrate andthe back substrate. After being disposed on a wall base, such a metalwall material is tightened to the wall base by driving a tighteningmember such as a nail or a screw.

CITATION LIST Patent Literature

Japanese Patent Application Publication No. S64-37826 A

SUMMARY OF INVENTION Technical Problem

When the tightening member is driven into the metal wall material asdescribed above, a pressure caused by the driving of the binding membermay lead to a depression or buckling around the driven position of thetightening member. Such a depression or buckling will cause retention ofmoisture such as rain water that will cause corrosion of the metal wallmaterial, and deterioration of the design of the metal wall material. Inorder to prevent the depression or buckling, a method of increasing asheet thickness of the front substrate can be considered. However, sucha method results in an increase in the weight of the wall.

The present invention has been made to solve the above problems. Anobject of the present invention is to provide a metal wall material thatcan decrease a depression and buckling in the front substrate due to thedriving of the tightening member, and a wall construction method usingthe same.

Solution to Problem

The present invention relates to a metal wall material comprising: afront substrate made of a metal sheet, the front substrate comprising abody portion formed into a box shape; a back substrate arranged on aback side of the front substrate so as to cover an opening of the bodyportion; and a core material filled between the body portion and theback substrate, the metal wall material being tightened to a wall baseby driving at least one tightening member into the body portion, whereina top plate portion of the body portion comprises at least oneprotruding rib comprised of at least one protrusion disposed along aside of a polygon or along a circle, and wherein the metal wall materialis configured such that the tightening member is driven into an innerregion of the protruding rib.

The present invention also relates to a wall construction method using ametal wall material comprising: a front substrate made of a metal sheet,the front substrate comprising a body portion formed into a box shape; aback substrate arranged on a back side of the front substrate so as tocover an opening of the body portion; and a core material filled betweenthe body portion and the back substrate, a top plate portion of the bodyportion comprising at least one protruding rib comprised of at least oneprotrusion disposed along a side of a polygon or along a circle, whereinthe wall construction method comprises the steps of: placing the metalwall material on a wall base; and driving at least one tightening memberinto an inner region of the protruding rib to tighten the metal wallmaterial to the wall base.

Advantageous Effects of Invention

According to the metal wall material and the wall construction methodusing the same according to the present invention, the protruding ribcomprised of at least one protrusion disposed along a side of a polygonor along a circle is provided on the top plate portion of the bodyportion and the tightening member is driven into the inner region of theprotruding rib, thereby enabling the depression or buckling in the frontsubstrate due to the driving of the tightening members to be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a front view showing a metal wall material according to anembodiment of the present invention.

FIG. 2 is a back view showing the metal wall material 1 in FIG. 1.

FIG. 3 is a cross-sectional view of the metal wall material taken alongthe line III-III in FIG. 1.

FIG. 4 is an explanatory view showing another aspect of the body portionin FIG. 1.

FIG. 5 is explanatory view showing a wall construction structure andwall construction method using the metal wall material 1 in FIG. 1.

FIG. 6 is an enlarged plan view of the region VI in FIG. 1.

FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6.

FIG. 8 is a plan view showing a circle that falls within the innerregion in FIG. 6.

FIG. 9 is explanatory view showing a variation of the protruding rib inFIG. 6.

FIG. 10 is explanatory view showing a further variation of theprotruding rib in FIG. 6.

FIG. 11 is an explanatory view showing a still another variation of theprotruding rib in FIG. 6.

DESCRIPTION OF EMBODIMENTS

Embodiments for carrying out the present invention will be describedwith reference to the drawings.

Embodiments for Carrying out the Present Invention:

FIG. 1 is a front view showing a metal wall material 1 according to anembodiment of the present invention, FIG. 2 is a back view showing themetal wall material 1 in FIG. 1, FIG. 3 is a cross-sectional view of themetal wall material 1 taken along the line III-III in FIG. 1, FIG. 4 isan explanatory view showing another aspect of the body portion in FIG.1, and FIG. 5 is explanatory view showing a wall construction structureand wall construction method using the metal wall material 1 in FIG. 1.

A metal wall member 1 as shown in FIGS. 1 to 3 is arranged together withother metal wall members on a wall base of a building such as a house,as shown in FIG. 5. As particularly shown in FIG. 3, the metal wallmember 1 includes a front substrate 10, a back substrate 11, and a corematerial 12.

The front substrate 10 is made of a metal sheet and appears on the outersurface of the wall as the metal wall material 1 is placed on the wallbase. The metal sheet making up the front substrate 10 that can be usedincludes a hot-dip Zn plated steel sheet, a hot-dip Al plated steelsheet, a hot-dip Zn plated stainless steel sheet, a hot-dip Al platedstainless steel sheet, a stainless steel sheet, an Al sheet, a Ti sheet,a coated hot-dip Zn plated steel sheet, a coated hot-dip Al plated steelsheet, a coated hot-dip Zn plated stainless steel sheet, a coatedhot-dip Al plated stainless steel sheet, a coated stainless steel sheet,a coated Al sheet or a coated Ti sheet.

Preferably, the thickness of the metal sheet is 0.5 mm or less. Anincreasing thickness of the metal sheet will result in increasedstrength of the wall material, while resulting in increased weight ofthe wall material. The thickness of the metal sheet of 0.5 mm or lesscan prevent the weight of the metal wall material 1 from becomingexcessive. In addition, the metal sheet has a thickness of 0.27 mm ormore. The thickness of the metal sheet of 0.27 mm or more can ensurestrength required for the wall, and sufficiently provide wind pressureresistance performance. The wind pressure resistance performance refersto performance for which the metal wall material 1 can withstand strongwind without buckling of the metal wall material 1.

The front substrate 10 includes a box-shaped body portion 100 having atop plate portion 101 and peripheral wall portions 102. The body portion100 is preferably formed by performing drawing or bulging processing ona metal sheet. By forming the box-shaped body portion 100 by performingthe drawing or bulging processing, each of the side wall portions 102can have a wall surface that is continuous in the circumferentialdirection of the front substrate 10, and any likelihood that waterenters the inside of the body portion 100 can be reduced. However, it isalso possible to bend the metal sheet having a shape as shown in FIG. 4along the dashed lines in the figure to form the box-shaped body portion100.

When the steel sheet (the hot-dip Zn plated steel sheet, the hot-dip Alplated steel sheet, the hot-dip Zn plated stainless steel sheet, thehot-dip Al plated stainless steel sheet, the stainless steel sheet, theAl sheet, the Ti sheet, the coated hot-dip Zn plated steel sheet, thecoated hot-dip Al plated steel sheet, the coated hot-dip Zn platedstainless steel sheet, the coated hot-dip Al plated stainless steelsheet or the coated stainless steel sheet) is used as the metal sheet ofthe front substrate 10 and when the body portion 100 is formed by thedrawing or bulging processing, the hardness of the peripheral wallportions 102 are increased by work hardening. More particularly, theVickers hardness of each peripheral wall portion 102 can be increased toabout 1.4 to 1.6 times the hardness before the working, The windpressure resistance performance of the metal wall member 1 issignificantly improved by virtue of the fact that each peripheral wallportion 102 has the wall surface that is continuous in thecircumferential direction of the front substrate 10, as described above,and by virtue of the fact that the hardness of each peripheral wallportion 102 is increased by work hardening.

The back substrate 11 is a member that is arranged on the back side ofthe front substrate 10 so as to covert an opening of the body portion100. The back substrate 11 that can be used include lightweightmaterials such as an aluminum foil, aluminum vapor deposited paper,aluminum hydroxide paper, calcium carbonate paper, resin films or glassfiber paper and the like. The use of these lightweight materials for theback substrate 11 allows prevention of an increase in the weight of themetal wall material 1.

The core material 12 is made of, for example a foamed resin or the like,and is filled between the body portion 100 of the front substrate 10 andthe back substrate 11. The filling of the core material 12 between thebody portion 100 of the front substrate 10 and the back substrate 11 canlead to a stronger adhesion of the core material 12 to the inside of thebody portion 100 as compared with an embodiment where a backing materialsuch as a resin sheet or the like is attached onto the back side of thefront substrate 11, so that the performance required for the wallmaterials, such as rainfall noise reduction, and heat insulation, can beimproved.

The material of the core material 12 includes, but not limited to, forexample, urethane, phenol and cyanurate resins. For wall materials,however, certified noncombustible materials are suitably used. The testfor certification of noncombustible material is conducted by a heatrelease test according to the cone calorimeter test method defined inISO 5660-1. If the foamed resin for forming the core material 12 isurethane having a higher calorific value or the like, the thickness ofthe core material 12 may be decreased, or inorganic expandable particlesmay be incorporated into the foamed resin.

A height h of the body portion 100 filled with the core material 12 ispreferably 4 mm or more and 8 mm or less. The height h of the bodyportion 100 of 4 mm or more enables sufficiently higher strength of thebody portion 100, and improved wind pressure resistance. The height h of4 mm or more can also provide improved heat insulation properties. Theheight h of the body portion 100 of 8 mm or less can prevent the organicmass of the core material 12 from becoming excessive, and can allowcertification of noncombustible material to be more reliably obtained.

As shown in FIG. 5, the metal wall material 1 is adapted such that awidth direction 100 a (a longitudinal direction) of the body portion 100extends along a direction 4 parallel to an eave of the wall, and a depthdirection 100 b (a short direction) of the body portion 100 as describedbelow extends along an upper-lower direction 5 of the wall. Each metalwall material 1 is fastened to the wall base by driving fasteningmembers such as screws or nails. Further, in the upper-lower direction5, the metal wall material 1 on the lower side is arranged on the wallbase while being overlapped onto the metal wall material 1 on the lowerside.

Returning to FIG. 1, the top plate portion 101 of the body portion 100includes a plurality of tightening indicators 2 spaced apart from eachother along the width direction 100 a of the body portion 100, and aprotruding rib 3 arranged around each tightening indicator 2. Thetightening indicators 2 and the protruding ribs 3 are described below inmore detail.

FIG. 6 is an enlarged plan view of the region VI in FIG. 1, FIG. 7 is across-sectional view taken along the line VII-VII in FIG. 6, and FIG. 8is a plan view showing a circle that falls within the inner region inFIG. 6. The tightening indicators 2 indicate positions for driving thetightening members into the metal wall material 1. As shown in FIGS. 6and 7, each of the tightening indicators 2 of this embodiment iscomposed of a concave portion having a circular shape in plan view.However, each of the tightening indicators 2 may present any other formin which the operator can visually or tactually recognize the tighteningposition of the tightening member, such as, for example, a convex body,an opening, or a printed or engraved symbol.

Each protruding rib 3 is formed by a plurality of protrusions 30disposed along a side of a rectangle extending in the depth direction100 b of the body portion 100. Each tightening indicator 2 is disposedin an inner region 3 a of each protruding rib 3. That is, the metal wallmaterial 1 according to the present embodiment is configured such thatthe tightening member is driven into the inner region 3 a of theprotruding rib 3, and the tightening member is driven into the innerregion 3 a of the protruding rib 3 when carrying out wall construction(creating a wall) as shown in FIG. 5.

As shown in FIG. 7, each protrusion 30 is structured by allowing a partof the metal sheet forming the top plate portion 101 to protrude. Avertical inner wall 30 a of each protrusion 30 extends in a directionintersecting with a wall surface of the inner region 3 a of theprotruding rib 3, and can be resistant to deformation of the innerregion 3 a when the tightening member is tightened to the inner region 3a (the tightening indicator 2) of the protruding rib 3. That is, thetightening member is driven into the inner region 3 a (the tighteningindicator 2) of the protruding rib 3, thereby reducing a depression orbuckling of the front substrate 10 due to the driving of the tighteningmember.

As shown in FIG. 6, each protruding rib 3 is provided with a pluralityof opening portions 31 that communicate an outer region 3 b with theinner region 3 a of the protruding rib 3. For the protruding rib 3according to the present embodiment, the four opening portions 31 areformed by lacking the protrusions 30 at both ends of the upper and lowersides of the rectangle. In the opening portion 31, surfaces under thesame conditions as those of the surfaces of the inner region 3 a and theouter region 3 b of the protruding rib 3 preferably extend. By providingthe opening portion 31 in the protruding rib 3, a flow of air passinginside and outside the protruding rib 3 can be ensured even if an upperportion of the protruding rib 3 is blocked by the other metal wallmaterial as shown in FIG. 5. This can allow evaporation of moisture suchas rainwater to be facilitated even if the moisture enters the innerregion 3 a of the protruding rib 3, thereby reducing any risk wheremoisture will remain in the inner region 3 a of the protruding rib 3.

Here, the opening portions 31 positioned at both ends of the lower sideof the rectangle form lower side opening portions 31E positioned on thelower sides of the protruding rib 3 when the metal wall material 1 isdisposed on the wall base. The lower side means a downstream side in aflow direction of the wall. By providing such lower side openingportions 31E, the moisture that has entered the inner region 3 a of theprotruding rib 3 can escape through the lower side opening portions 31Eto the outer region 3 b of the protruding rib 3, thereby enabling a riskwhere the moisture will remain in the inner region 3 a of the protrudingrib 3 to be reduced.

A ratio of the opening portions 31 in each protruding rib 3 (hereinafterreferred to as an opening ratio) is preferably 50% or less. The openingratio can be defined by the following equation:

Opening Ratio (%)=(Total of Center Angles Corresponding to OpeningPortions/360)×100

The center angles corresponding to the opening portions are angles θ1 toθn between straight lines corresponding to the respective openingportions 31 a when a circle having the largest radius that falls withinthe inner region 3 a is drawn as shown in FIG. 8, and the straight linespassing through the center of the circle and both inner ends of eachopening portion 31 a are drawn. In the case of the embodiment where thefour opening portions 31 a are provided on the protruding rib 3 as shownin FIG. 8, it is expressed as the opening ratio(%)={(θ1+θ2+θ3+θ4)/360}×100. The circle that falls within the innerregion 3 a means a circle that is located inside the protruding rib 3and that does not extend beyond the vertical inner wall 30 a of all theprotruding portions 30. Further, the symbol n is an arbitrary positivenumber corresponding to the number of opening portions 31. As will bedescribed later with reference to Examples, the opening ratio of theprotruding rib 3 of 50% or less can suppress deformation of the frontsubstrate 10 due to the driving of the tightening member to a smallerlevel.

Each protrusion 30 preferably has a height H of 0.2 mm or more. Theheight H corresponds to a distance between a surface of the inner region3 a or the outer region 3 b of the protruding rib 3 and a top of theprotruding portion 30. As will be described later with reference toExamples, the height of each protrusion 30 of 0.2 mm or more cansuppress the deformation of the front substrate 10 due to the driving ofthe tightening member to a smaller level.

A value (W/H) obtained by dividing a width W of each protrusion 30 bythe height H of each protrusion 30 is preferably 3 or more. The width Wcorresponds to a distance between the vertical inner wall 30 a and avertical outer wall of the protrusion 30. As will be described laterwith reference to Examples, the value of W/H of 3 or more can avoid theprocessing of forming the protrusions 30 from being severe, and morereliably avoid cracks from occurring in a coated film formed on thesurface of the metal sheet forming the top plate portion 101.

It is preferable that a shortest distance L from the center position ofthe inner region 3 a to each protrusion 30 is 5 mm or more and 20 mm orless. The shortest distance L from the center position of the innerregion 3 a to each protrusion 30 can be defined by a radius of a circlehaving the largest radius that falls within the inner region 3 a (seeFIG. 8). As will be described later with reference to Examples, theshortest distance L of 5 mm or more and 20 mm or less can suppress thedeformation of the front substrate 10 due to the driving of thetightening member to a smaller level.

Next, FIG. 9 is explanatory view showing a variation of the protrudingrib 3 in FIG. 6. As shown in FIGS. 9(a) to 9(h), the protrusion(s) 30forming each protruding rib 3 may be arranged along a circle. As shownin FIGS. 9(a), (e), (f) and (g), the protruding rib 3 may be structuredby one protruding portion 30, and as shown in FIGS. 9(b) to (d) and (h),the protruding rib 3 may be structured by a plurality of protrudingportions 30.

As shown in FIGS. 9(b) to 9(d), a plurality of opening portions 31 maybe arranged to face each other with the center positions of theprotruding rib 3 interposed therebetween, or as shown in FIGS. 9(e) and(f), one opening portion 31 may be provided such that the opening rateof the protruding rib 3 is 50%. As shown in FIG. 9(h), a part of theopening portions 31 may be the lower side opening portion 31E while theopening ratio of the protruding rib 3 is 50%.

Next, FIG. 10 is explanatory view showing a further variation of theprotruding rib 3 in FIG. 6. As shown in FIGS. 10(a) to 10(h), theprotrusion(s) 30 forming each protruding rib 3 may be disposed along aside of a square. As shown in FIGS. 10(a) and 10(e), the protruding rib3 may be structured by one protrusion 30. As shown in FIGS. 10(b) to10(d) and FIGS. 10(f) to (h), the protruding rib 3 may be structured bya plurality of protrusions 30.

As shown in FIGS. 10(b) to (d), (f) and (g), a plurality of openingportions 31 may be arranged to face each other with the center positionsof the protruding rib 3 interposed therebetween, or as shown in FIG.10(e), one opening portion 31 may be provided such that the openingratio of the protruding rib 3 is 50%. As shown in FIG. 10(h), a part ofthe opening portions 31 may be the lower opening portion 31E while theopening ratio of the protruding rib 3 is 50%.

Next, FIG. 11 is explanatory view showing other variation of theprotruding rib 3 in FIG. 6. As shown in FIGS. 11(a) to 11(e), theprotruding portion 30 forming the protruding rib 3 may be disposed alongsides of a triangle, a rhombus (quadrangle), a pentagon and an octagon.Further, the protrusion 30 may be arrange along sides of a polygonhaving twist angles. Even if the protrusions 30 are arranged along thesides of the triangle, rhombus (quadrangle), pentagon and octagon asshown in FIGS. 11(a) to (e), the opening portion(s) can be provided asshown in FIGS. 9 and 10.

EXAMPLES

Examples are now illustrated, The inventors experimentally producedsamples of the metal wall material 1 under conditions given below.

A coated hot-dip Zn-55% Al plated steel sheet, a coated hot-dip Zn-6%Al-3% Mg plated steel sheet or a coated hot-dip Al plated steel sheet,which had a size of 0.20 mm to 0.6 mm, was used as the material of thefront substrate 10.

Glass fiber paper having a size of 0.2 mm, Al metallized paper having asize of 0.2 mm, a PE resin film having a size of 0.2 mm, an Al foilhaving a size of 0.1 mm or a coated hot-dip Zn plated steel sheet havinga size of 0.27 mm was used as the back substrate 11.

A two-liquid mixture type foam resin was used as the core material 12.The mixing ratio of a polyol component and isocyanate, phenol orcyanurate component was 1:1, in a ratio by weight.

The front substrate 10 was processed to have a predetermined thicknessand shape of the wall material. The back substrate 11 was then disposedon the back side of the front substrate 10 so as to cover the opening ofthe body portion 100, and the foam resin was injected into the gapbetween the body portion 100 of the front substrate 10 and the backsubstrate 11, using a commercially available high-pressure injectionmachine. Foaming of the resin was accomplished by maintaining the resinfor 2 minutes in a mold at which the temperature was adjusted to 70° C.by circulating hot water; subsequently, the wall material was removedfrom the mold, and was allowed to stand for 5 minutes at roomtemperature of 20° C., to complete foaming of the resin.

After complete of the foaming of the resin, the metal sheet extendingfrom a lower edge of the body portion 100 toward the outer direction ofthe body portion 100 was cut such that a protruding width of a flangewas 5 mm, and the cut metal sheet was subjected to a bending process bymeans of a bender to have a predetermined shape. The dimensions of thefinal metal wall member 1 were 414 mm×910 mm. The thickness of the finalwall material was in the range of from 3 mm to 8 mm.

Such samples were subjected to the following evaluations: (1) evaluationof the weight of the wall material; (2) evaluation of a depressionduring tightening; (3) evaluation of cracking on the coated film; and(4) evaluation of ease of rainwater flow, while changing the shape ofeach protruding rib 3, the presence or absence of the lower side openingportion 31E, the height H of the protruding portion 30, the shortestdistance L from the center position of the inner region 3 a to theprotruding portion 30, the value obtained by dividing the width W of theprotrusion 30 by the height H of the protrusion 30, and the openingratio (a ratio of the opening portions 31 in the protruding rib 3). Theresults are shown in the Table as shown below.

TABLE 1 Details of Samples and Performance Evaluation Results Details ofSamples Presence or Performance Evaluation Results Absence of ProtrusionCracking Easeof Thick- Eave Lower Protrusion Shortest Width W WallDepression on Rain- ness Rib Side Height Distance Protrusion OpeningMaterial during Coated water Classification (mm) Shape Opening H (mm) L(mm) Height H Ratio (%) Weight Tightening Film Flow Examples 1 0.3Circular Present 0.3 10 17 10 ◯ ◯ ◯ ◯ 2 0.3 Rectangular Present 0.3 1017 12.5 ◯ ◯ ◯ ◯ 3 0.3 Triangular Present 0.8 15 19 20 ◯ ◯ ◯ ◯ 4 0.35Pentagonal Present 1 20 10 40 ◯ ◯ ◯ ◯ 5 0.35 Hexagonal Present 1 20 1040 ◯ ◯ ◯ ◯ 6 0.5 Hexagonal Present 1 20 3 40 ◯ ◯ ◯ ◯ 7 0.4 CircularPresent 0.5 10 10 15 ◯ ◯ ◯ ◯ Comparative 1 0.6 Triangular Present 0.5 1010 30 Δ ◯ ◯ ◯ Examples 2 0.3 Square Absent 0.3 10 10 52 ◯ Δ ◯ Δ 3 0.3Square Present 0.3 23 15 15 ◯ Δ ◯ ◯ 4 0.4 Pentagonal Present 0.1 10 1015 ◯ Δ ◯ ◯ 5 0.4 Hexagonal Present 0.3 10 2 15 ◯ ◯ Δ ◯ 6 0.4 CircularPresent 1.1 10 2.7 15 ◯ ◯ Δ ◯ 7 0.27 Circular Absent 0.2 5 15 0 ◯ ◯ ◯ Δ8 0.3 Square Absent 0.3 5 10 0 ◯ ◯ ◯ Δ

(1) Evaluation Criteria of Wall Material Weight

The unit weight of each wall material was measured and evaluated fromconstruction properties in accordance with the following criteria.

∘: unit weight of wall material of less than 20 N/sheet; and

Δ: unit weight of wall material of 20 N/sheet or more.

(2) Evaluation Criteria of Depression during Tightening

As the tightening member, a commercially available best screw (adiameter of 4.0 mmφ×a length of 35 mm) from YAMAKI SANGYO co., ltd., andan impact driver (TD136D from Makita Corporation) were used to tightentwo wall material sheets stacked to each other. For the depressionduring the tightening, the depression of the tightened wall material onthe upper side were measured by means of a gap gauge and evaluatedaccording to the following evaluation criteria:

∘: Depression of less than 2 mm during tightening; and

Δ: Depression of 2 mm or more during tightening.

(3) Evaluation of Cracking on Coated Film

The cracking on the coated film which occurred on a coated steel sheetwhen forming the protrusion 30 was visually observed with a magnifyingglass at magnitudes of 10 times, and evaluated according to thefollowing evaluation criteria:

∘: No cracking on the coated film was observed or minor cracking wasobserved; and

Δ: Significant cracking on the coated film was observed.

(4) Ease of Rainwater Flow

The wall material was inclined at a gradient of 15°, 1000 mL of tapwater was allowed to flow over the wall material, and a situation wherethe water remained in the inner region 3 a of the protruding rib 3 wasvisually evaluated according to the following evaluation criteria:

∘: Water fluently flowed and almost no water remained in the innerregion;

Δ: Water remained.

As shown in Comparative Example 1, when the thickness of the metal sheetforming the front substrate 10 was 0.6 mm, the unit weight of the wallmaterial was 250 N/m² or more, and the weight of the wall material wasevaluated as Δ. On the other hand, as shown in the Examples, the unitweight of the wall material was able to be less than 20 N/sheet by thethickness of the metal sheet forming the front substrate 10 being 0.5 mmor less. These results indicated that the thickness of the metal sheetforming the front substrate 10 is preferably 0.5 mm or less.

As shown in Comparative Example 2, when the opening ratio of theprotruding rib 3 was more than 50%, the depression during tightening was2 mm or more, and the depression during tightening was evaluated as Δ.On the other hand, as shown in Examples, when the opening ratio was 50%or less, the depression during tightening could be less than 2 mm. Theseresults indicated that the opening ratio is preferably 50% or less.

As shown in Comparative Example 3, when the shortest distance L from thecenter position of the inner region 3 a to the protrusion 30 was morethan 20 mm, the depression during tightening was 2 mm or more, and thedepression during tightening was evaluated as Δ. On the other hand, asshown in Examples, when the shortest distance L was 20 mm or less, thedepression during tightening could be less than 2 mm. These resultindicated that the shortest distance L is preferably 20 mm or less. Inaddition, when the shortest distance L is decreased, the protrusion 30may become a barrier and hinder the fastening work when the wallmaterial is fastened by a nail or a screw using a hammer, a driver, oran electric tool. For this reason, the shortest distance L is preferably5 mm or more.

As shown in Comparative Example 4, when the height H of the protrusion30 was less than 0.2 mm, the depression during tightening was 2 mm ormore, and the depression during tightening was evaluated as Δ. On theother hand, as shown in Examples, when the height H of the protrusion 30was 0.2 mm or more, the depression during tightening could be less than2 mm. These result indicated that the height H of the protrusion 30 ispreferably 0.2 mm or more.

As shown in Comparative Examples 5 and 6, when the value obtained bydividing the width W of the protrusion 30 by the height H of theprotrusion 30 was less than 3, cracking occurred on the coated film, andthe cracking on the coated film was evaluated as Δ. On the other hand,as shown in Examples, when the value obtained by dividing the width W ofthe protrusion 30 by the height H of the protrusion 30 was 3 or more,the cracking on the coated film could be avoided. These resultsindicated that the value obtained by dividing the width W of theprotrusion 30 by the height H of the protrusion 30 is preferably 3 ormore.

As shown in Comparative Examples 2, 7, and 8, when the lower sideopening portion 31E was not provided, water remained in the inner region3 a of the protruding rib 3, and the ease of rainwater flow wasevaluated as Δ. On the other hand, as shown in the Examples, when thelower side opening portion(s) 31E was/were provided, water remaining inthe inner region 3 a of the protruding rib 3 could be avoided. Theseresults indicated that it is preferable to provide the lower sideopening portion(s) 31E.

In the metal wall material 1 and the wall construction method using themetal wall material 1, the top plate portion 101 of the body portion 100comprises at least one protruding rib 3 composed of at least oneprotruding portion 30 disposed along the side of the polygon or alongthe circle, and the tightening member is driven into the inner region 3a of the protruding rib 3, so that the depression or buckling of thefront substrate 10 due to the driving of the tightening member can bereduced.

Further, the protruding rib 3 is provided with at least one openingportion 31 for communicating the outer region 3 b with the inner region3 a of the protruding rib 3, so that the flow of air passing inside andoutside the protruding rib 3 can be ensured even if the upper portion ofthe projected rib 3 is blocked by the other metal wall material. Thus,even if moisture such as rainwater enters the inner region 3 a of theprotruding rib 3, evaporation of the water can be promoted, therebyreducing a risk where moisture remains in the inner region 3 a of theprotruding rib 3.

Furthermore, at least one opening portion 31 includes an lower sideopening portion 31E located on the lower side of the protruding rib 3when the metal wall material 1 is disposed on the wall base, so thatmoisture that has entered the inner region 3 a can escape through thelower side opening portion 31E to the outer region 3 b of the protrudingrib 3, thereby reducing a risk where the moisture will remain in theinner region 3 a of the protruding rib 3.

Moreover, the ratio (opening ratio) of the opening portions 31 in theprotruding rib 3 is 50% or less, so that deformation of the frontsubstrate 10 due to the driving of the tightening member can besuppressed to a smaller level.

Also, the height H of the protrusion 30 is 0.2 mm or more, so thatdeformation of the front substrate 10 due to the driving of thetightening member can be suppressed to a smaller level.

Further, the value (W/H) obtained by dividing the width W of theprotrusion 30 by the height H of the protrusion 30 is 3 or more, so thatcracking can be more reliably prevented from occurring on the coatedfilm formed on the surface of the metal sheet forming the top plateportion 101.

Furthermore, the shortest distance from the center position of the innerregion 3 a to the protrusion 30 is 5 mm or more and 20 mm or less, sothat deformation of the front substrate 10 due to the driving of thetightening member can be suppressed to a smaller level.

Moreover, the sheet thickness of the metal sheet forming the frontsubstrate 10 is 0.5 mm or less, so that excessively increased weight ofthe metal wall material 1 can be more reliably avoided.

1. A metal wall material comprising: a front substrate made of a metalsheet, the front substrate comprising a body portion formed into a boxshape; a back substrate arranged on a back side of the front substrateso as to cover an opening of the body portion; and a core materialfilled between the body portion and the back substrate, the metal wallmaterial being tightened to a wall base by driving at least onetightening member into the body portion, wherein a top plate portion ofthe body portion comprises a protruding rib comprised of at least oneprotrusion disposed along a side of a polygon or along a circle, andwherein the metal wall material is configured such that the tighteningmember is driven into an inner region of the protruding rib.
 2. Themetal wall material according to claim 1, wherein the protruding ribcomprises at least one opening portion that communicates an outer regionwith the inner region of the protruding rib.
 3. The metal wall materialaccording to claim 2, wherein the at least one opening portion includesa lower side opening portion located on a lower side of the protrudingrib when the metal wall material is disposed on the wall base.
 4. Themetal wall material according to claim 2, wherein a ratio of the openingportions in the protruding rib is 50% or less.
 5. The metal wallmaterial according to claim 1, wherein the protrusion has a height of0.2 mm or more.
 6. The metal wall material according to claim 5, whereina value obtained by dividing a width of the protrusion by the height ofthe protrusion is 3 or more.
 7. The metal wall material according toclaim 1, wherein a shortest distance from a center position of the innerregion to the protrusion is 5 mm or more and 20 mm or less.
 8. The metalwall material according to claim 1, wherein the metal sheet forming thefront substrate has a thickness of 0.5 mm or less.
 9. A wallconstruction method using a metal wall material comprising: a frontsubstrate made of a metal sheet, the front substrate comprising a bodyportion formed into a box shape; a back substrate arranged on a backside of the front substrate so as to cover an opening of the bodyportion; and a core material filled between the body portion and theback substrate, a top plate portion of the body portion comprising aprotruding rib comprised of at least one protrusion disposed along aside of a polygon or along a circle, the wall construction methodcomprising the steps of: placing the metal wall material on a wall base;and driving at least one tightening member into an inner region of theprotruding rib to tighten the metal wall material to the wall base.